IFFP Modules - July 1991 version 37.5 These iffparse.library code modules and examples are designed as replacements for the original EA IFF code. In some modules, it has been possible to retain much of the original code. However, most structures and most higher level function interfaces have changed. On the plus side, these new modules contain many new high-level easy-to-use functions for querying, loading, displaying, and saving ILBMs. During their development, modules similar to these have been used inhouse at Commodore for the 2.0 Display program and several other ILBM applications. The screen.c module provides powerful display-opening functions which are 1.3-compatible yet provide a host of new options under 2.0 such as centered overscan screens, full-video display clips, border transparency control, and autoscroll. New modules have been added for printing (screendump) and for preserving/adding chunks (copychunks). And the 8SVX example now actually plays samples and instruments. In addition, clipboard support is automatic for all applications that use the IFFP modules because parse.c's openifile() interprets the filename -c[n] (ie. "-c", "-c1", "-c2", etc.) as clipboard unit n. All of the applications presented here require iffparse.library which is distributed on Workbench 2.0. Please note that iffparse.library is a 1.3-compatible library, and that all of these modules and examples have been designed to take advantage of 2.0, but also work under 1.3. Developers who wish to distribute iffparse.library on their commercial products may execute a 2.0 Workbench license, or may get an addendum to their 1.3 Workbench license to allow distribution of iffparse.library. It was not necessary to port the gio IO speedup code since iffparse can use your compiler's own buffered IO routines through the callback stdio_stream() in parse.c. Depending on your application, you may want to add your own additional buffering to this stdio_stream() code. Most of the high-level function pairs provided in these modules have been designed to provide safe cleanup for themselves. For example, a loadbrush() that succeeds or fails at any point can be cleaned up via unloadbrush. The cleanup routines null out the appropriate pointers so that allocations will not be freed twice. All applications are built upon the parse.c module. The basic concept of using the parse.c module are: - Define tag-like arrays of your desired chunks (readers only) - Allocates one or more [form]Info structures as defined in iffp/[form]app.h (for example an ILBMInfo defined in iffp/ilbmapp.h). - Initialize the ParseInfo part of these structures to the desired chunk arrays, and to an IFFHandle allocated via iffparse AllocIFF(). - Use the provided high level load/save functions, or use the lower level parse.c openifile(), reader-only parseifile()/ getcontext()/nextcontext(), and closeifile(). The filename -c[n] may be used to read/write clipboard unit n. - Clean up, FreeIFF(), and deallocate [form]Info's. IMPORTANT NOTES - Most of the higher-level load functions keep the IFFHandle (file or clipboard) open. While the handle is open, you may use parse.c functions (such as findpropdata) OR direct iffparse functions (FindProp(), FindCollection()) for accessing the gathered chunks. However, it is not a good idea to keep a filehandle OR the clipboard open. While a clipboard unit is open, no other applications can clip to the unit. And while a file is open, you can't write the file back out. So, instead of keeping the file or unit open, you can use copychunks (in copychunks.c) to create a copy of your gathered chunks, and do an early closeifile() (parse.c). Then access and later write back out (if you wish) and deallocate your copied chunks via the routines in the copychunks module (findchunk, writechunklist, freechunklist). WARNING REGARDING COMPLEX FORMS Regarding Complex FORMs - The parse.c module will enter complex formats such as CATSs, LISTs, and nested FORMs to find the FORM that you are interested in. This is great. However, if you are a read-modify-write program, you should warn your user when this occurs unless YOU are capable of recreating the complex format. Otherwise, your user may unknowingly destroy his complex file by writing over it with your program. Example - a paint program could read an ILBM out of a complex LIST containing pictures and music, and then save it back out as a simple ILBM, causing the user to lose his music and other pictures. To determine if a complex form was entered after a load, check the (form)Info.ParseInfo.hunt field. If TRUE (non-zero), then your file was found inside a complex format. COMPILATION NOTES These modules and examples have been compiled using SAS C 5.10a and Manx C 5.0d, with 2.0 (37.1) include files and 2.0 amiga.lib. You must have at least 37.1 alib_protos.h (older versions of this include file contained the amiga.lib stdio protos also which conflict with both SAS and Manx stdio). For Manx, I also had to comment out the conditional definition of abs() in libraries/mathffp.h. These modules do not use mathffp, but the mathffp include file is pulled in by alib_protos.h. When compiling with Manx, a warning seems to be generated for each string constant assigned to a UBYTE * field, and also by some references to ilbm->colortable. LIST OF IFFP MODULES AND APPLICATIONS ------------------------------------- NOTE - Some useful functions are listed with each module See module source code for docs on each function. APPLICATIONS (these require linkage with modules - see Makefiles) ------------ ILBMDemo Displays an ILBM, loads a brush, saves an ILBM, opt. print ILBMLoad Queries an ILBM and loads it into an existing screen ILBMtoC Outputs an ILBM as C source code ILBMtoRaw Converts an ILBM to raw plane/color file RawtoILBM Converts raw plane/color file (from ILBMtoRaw) to an ILBM 24bitDemo Saves a simple 24-bit ILBM and then shows it 4 planes at a time (if given filename, just does the show part) Play8SVX Reads and plays an 8SVX sound effect or instrument - LoadSample, UnloadSample, PlaySample, OpenAudio, CloseAudio, and body load/unpack functions ScreenSave Save the front screen as an ILBM, with an icon OTHER EXAMPLES (use iffparse.library directly and require no modules) -------------- Sift Checks and prints outline of any IFF file (uses RAWSTEP) ILBMScan Prints out useful info about any ILBM ClipFTXT Demonstrates simply clipping of FTXT to/from clipboard cycvb.c Dan Silva's routine for interrupt based color cycling apack.asm Dr. Gerald Hull's assembler replacement for packer.c GENERAL IFFPARSE SUPPORT MODULE ------------------------------- parse.c File/clipboard IO and general parsing - openifile, closeifile, parseifile, getcontext, nextcontext, contextis, currentchunkis, PutCk chunk writing function, and IFFerr text error routine ILBM READ MODULES ----------------- loadilbm.c High level ILBM load routines which are passed filenames (calls getbitmap) - loadbrush/unloadbrush,loadilbm/unloadilbm,and queryilbm getbitmap.c brush/bitmap loading (non-display, calls ilbmr.c) - createbrush/deletebrush, getbitmap/freebitmap getdisplay.c bitmap load/display (calls screen.c, ilbmr.c) - showilbm/unshowilbm, createdisplay/deletedisplay screen.c 1.3/2.0 ECS/non-ECS compatible screen/window module - opendisplay, openidscreen, modefallback, clipit ilbmr.c Lower level ILBM body/color load routines(calls unpacker.c) - loadbody, loadcmap, getcolors/freecolors, alloccolortable, getcamg (gets or creates modeid) unpacker.c BODY unpacker ILBM WRITE MODULES ------------------ saveilbm.c High level ILBM saving routines which are passed filenames (calls ilbmw.c) - screensave and saveilbm ilbmw.c Lower level ILBM body/color save routines (calls packer.c) - InitBMHD, PutCMAP, PutBODY packer.c BODY packer EXTRA MODULES ------------- copychunks.c Chunk cloning and chunk list writing routines - copychunks, findchunk, writechunklist, freechunklist screendump.c Screen printing module (iffparse not required) bmprintc.c Module to output ILBM as C code INCLUDE FILES ------------- iffp/#?.h This subdirectory may be kept in your current directory or in your main include directory. Thanks to Steve Walton for his code changes for Manx/SAS compatibility, and to Bill Barton and John Bittner for their comments and suggestions.
[Back to Amiga Developer Docs]